If Brown-headed Nuthatches haven't naturally recolonized Missouri since disappearing 100 years ago, with nearby populations in Arkansas, despite the recent restoration of habitat to "fill in," couldn't it be just as likely for this westward individual to be from Missouri? Ebird maps don't show the species to be particularly dense through most of their range, and apparently sedentary enough and not dense enough to recolonize MO without human assistance. And if these transplants were released in an area that somehow wasn't fit to be naturally recolonized, might there be a chance a relocated bird found it somehow unsuitable still, and wandered westward almost to CO? I'd have to dig out Pulich's "Birds of North Central Texas" to confirm, but I remember something like Dallas County Texas having zero records of BHNU despite them being resident just a stone's throw away in E TX pineywoods, while instead having a record of a vagrant Pygmy Nuthatch that wandered much farther - just an anecdote about how sedentary BHNU seems to be. The BHNU and PYNU sisters sure seem like good indicator species and picky about their forests.
Just rambling and musing here, trying to see the world through a nuthatches eyes for a moment.
"Apparently sedentary year-round [BHNU]....
Of 49 territorial, color-marked birds in Long Pine Key, Everglades
National Park that were present for > 2 years, 36 (73.4%) occupied
the same territory every year, for up to 6 consecutive years (G. L.
Slater, unpublished data). The remaining 13 (26.6%) switched territories
between years, but no individual switched territories more than once
during the period of observation (1998-2006; GLS, JDL). Studies of
marked birds outside of breeding season lacking and thus details of
winter home range remain unclear. Incidental observations of banded
individuals on or near breeding territories during the winter suggest
year-round residency...
Measurable genetic differentiation between nearby breeding populations (separated by <40 km; Haas et al. 2010), tendency of SY males to
remain on or near natal territories (Cox and Slater 2007), and failure
to recolonize vacant but suitable habitat (e.g., Long Pine Key,
Everglades National Park; Lloyd et al. 2009) suggest that movement among
populations limited." <
https://birdsoftheworld.org/bow/species/bnhnut/cur/demography>
Not venturing a guess on where the KS bird was born really... I have no idea! Scrutinize any wayward Pygmies out on the plains , some sharp eyes and ears will pick one out in CO some day! I bet it'll be in a small town cemetery with a few nice pine trees.
RE the Arctic Tern in Larimer @ Horseshoe - what's the best access point to scan the lake? Congrats to Josh Bruening on finding this awesome bird!
Good birding & Happy Halloween!
Derek Hill
Loveland